pragma solidity 0.4.16; contract token { string public standard = 'yuyangray'; string public name; //代币名称 string public symbol; //代币符号比如'$' //代币单位,展示的小数点后面多少个0,和以太币一样后面是是18个0 uint8 public decimals = 2; uint256 public totalSupply; //代币总量 mapping (address => uint256) public balanceOf; event Transfer(address indexed from, address indexed to, uint256 value); function token(address _owned, string tokenName, string tokenSymbol) public { //合约的管理者获得的代币总量 balanceOf[_owned] = totalSupply; name = tokenName; symbol = tokenSymbol; } function transfer(address _to, uint256 _value) public { //从发送者减掉发送额 balanceOf[msg.sender] -= _value; //给接收者加上相同的量 balanceOf[_to] += _value; //通知任何监听该交易的客户端 Transfer(msg.sender, _to, _value); } /** * 增加代币,并将代币发送给捐赠新用户 * @param _to address 接受代币的地址 * @param _amount uint256 接受代币的数量 */ function issue(address _to, uint256 _amount) public { totalSupply = totalSupply + _amount; balanceOf[_to] += _amount; //通知任何监听该交易的客户端 Transfer(this, _to, _amount); } } /** * 众筹合约 */ contract Crowdsale is token { address public beneficiary = msg.sender; //受益人地址,测试时为合约创建者 uint public fundingGoal; //众筹目标,单位是ether uint public amountRaised; //已筹集金额数量, 单位是ether uint public deadline; //截止时间 uint public price; //代币价格 bool public fundingGoalReached = false; //达成众筹目标 bool public crowdsaleClosed = false; //众筹关闭 mapping(address => uint256) public balance; //保存众筹地址及对应的以太币数量 // 受益人将众筹金额转走的通知 event GoalReached(address _beneficiary, uint _amountRaised); // 用来记录众筹资金变动的通知,_isContribution表示是否是捐赠,因为有可能是捐赠者退出或发起者转移众筹资金 event FundTransfer(address _backer, uint _amount, bool _isContribution); /** * 初始化构造函数 * * @param fundingGoalInEthers 众筹以太币总量 * @param durationInMinutes 众筹截止,单位是分钟 * @param tokenName 代币名称 * @param tokenSymbol 代币符号 */ function Crowdsale( uint fundingGoalInEthers, uint durationInMinutes, string tokenName, string tokenSymbol ) token(this, tokenName, tokenSymbol) public { fundingGoal = fundingGoalInEthers * 1 ether; deadline = now + durationInMinutes * 1 minutes; price = 500 finney; //1个以太币可以买 2 个代币 } /** * 默认函数 * * 默认函数,可以向合约直接打款 */ function () payable public { //判断是否关闭众筹 require(!crowdsaleClosed); uint amount = msg.value; //捐款人的金额累加 balance[msg.sender] += amount; //捐款总额累加 amountRaised += amount; //转帐操作,转多少代币给捐款人 issue(msg.sender, amount / price * 10 ** uint256(decimals)); FundTransfer(msg.sender, amount, true); } /** * 判断是否已经过了众筹截止限期 */ modifier afterDeadline() { if (now >= deadline) _; } /** * 检测众筹目标是否已经达到 */ function checkGoalReached() afterDeadline public { if (amountRaised >= fundingGoal){ //达成众筹目标 fundingGoalReached = true; GoalReached(beneficiary, amountRaised); } //关闭众筹 crowdsaleClosed = true; } /** * 收回资金 * * 检查是否达到了目标或时间限制,如果有,并且达到了资金目标, * 将全部金额发送给受益人。如果没有达到目标,每个贡献者都可以退出 * 他们贡献的金额 * 注:这里代码应该是限制了众筹时间结束且众筹目标没有达成的情况下才允许退出。如果去掉限制条件afterDeadline,应该是可以允许众筹时间还未到且众筹目标没有达成的情况下退出 */ function safeWithdrawal() afterDeadline public { //如果没有达成众筹目标 if (!fundingGoalReached) { //获取合约调用者已捐款余额 uint amount = balance[msg.sender]; if (amount > 0) { //返回合约发起者所有余额 msg.sender.transfer(amount); FundTransfer(msg.sender, amount, false); balance[msg.sender] = 0; } } //如果达成众筹目标,并且合约调用者是受益人 if (fundingGoalReached && beneficiary == msg.sender) { //将所有捐款从合约中给受益人 beneficiary.transfer(amountRaised); FundTransfer(beneficiary, amount, false); } } }
0.4.16